MOC3031FM Equivalent & Substitute Parts

Part Overview

The MOC3031FM is a 7.5kV optoisolator with triac output manufactured by onsemi, designed for applications requiring galvanic isolation and AC switching control. This component features a zero-crossing circuit and single-channel configuration in a 6-SMD surface mount package. The product is currently obsolete, making identification of compatible substitute parts essential for ongoing system support and new design implementations.

Substiute Parts

MOC3031FM

onsemiIn Stock: 959MOC3031FM Datasheet

Current PartRFQ

MOC3031SM

Fairchild SemiconductorIn Stock: 10158MOC3031SM Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MOC3031FM is determined by the following critical parameters:

• Output Type: Must be Triac output for AC switching functionality
• Zero Crossing Circuit: Must include zero-crossing detection for synchronized switching
• Number of Channels: Must be single-channel configuration
• Voltage - Isolation: Minimum 4170Vrms (equivalent to 5900Vpk) acceptable; 7500Vpk preferred for full compatibility
• Voltage - Off State: Must support 250 V minimum
• Current - LED Trigger (Ift): Maximum 15mA for input drive compatibility
• Current - Hold (Ih): 400µA typical for holding current
• Current - DC Forward (If): Maximum 60 mA for LED forward current
• Package / Case: 6-SMD, Gull Wing for PCB layout compatibility
• Mounting Type: Surface Mount required

The MOC3031SM meets these substitution criteria with equivalent electrical characteristics and compatible packaging, though with a lower isolation voltage rating (4170Vrms vs. 7500Vpk).

Parameter Comparison

Engineering Selection Recommendations

The MOC3031SM qualifies as a direct substitute for the obsolete MOC3031FM based on matching electrical specifications and identical package configuration. Selection should be guided by the following criteria:

Isolation Voltage Requirement: The MOC3031FM provides 7500Vpk isolation, while the MOC3031SM provides 4170Vrms (approximately 5900Vpk). Applications requiring isolation voltage exceeding 4170Vrms should not use the MOC3031SM as a substitute. Applications operating at or below 4170Vrms isolation requirements can safely implement the MOC3031SM.

Compliance and Certification: The MOC3031SM carries active product status with ROHS3 compliance and UL/VDE approvals, providing regulatory advantages over the obsolete MOC3031FM for new designs and manufacturing continuity.

Thermal Operating Range: The MOC3031SM specifies an operating temperature range of -40°C to 85°C, whereas the MOC3031FM does not provide this specification. Designs requiring operation outside this range should verify compatibility with the original MOC3031FM datasheet.

Manufacturing Availability: The MOC3031SM is actively manufactured with substantial inventory availability (10,100 pieces), ensuring supply chain continuity compared to the obsolete MOC3031FM.

Frequently Asked Questions (FAQ)

Q: Can the MOC3031SM directly replace the MOC3031FM in all applications?

A: The MOC3031SM is electrically compatible for applications where isolation voltage requirements do not exceed 4170Vrms. The MOC3031FM's 7500Vpk isolation rating is higher. Verify your application's isolation voltage specification before substitution.

Q: Are the package dimensions identical between MOC3031FM and MOC3031SM?

A: Both components use 6-SMD, Gull Wing surface mount packaging, ensuring PCB layout compatibility without redesign.

Q: What is the difference between 7500Vpk and 4170Vrms isolation ratings?

A: These are different measurement standards for isolation voltage. 7500Vpk (peak voltage) and 4170Vrms (RMS voltage) represent the maximum voltage that can be safely applied across the isolation barrier. The MOC3031FM supports higher isolation voltage than the MOC3031SM.

Q: Does the MOC3031SM meet current regulatory requirements?

A: Yes, the MOC3031SM is ROHS3 compliant and carries UL and VDE approvals, meeting current regulatory standards. The obsolete MOC3031FM does not carry these certifications.

Q: Are the LED trigger current and hold current specifications identical?

A: Yes, both components specify 15mA maximum LED trigger current (Ift) and 400µA typical hold current (Ih), ensuring input drive circuit compatibility.

Q: What is the operating temperature range for each component?

A: The MOC3031SM specifies -40°C to 85°C operating temperature. The MOC3031FM does not provide an operating temperature specification in the available data.